The present invention relates to a confocal scanning laser microscope.
The fundamental arrangement of a confocal scanning laser microscope (described in Appl. Phys. B27. 211-213 (1982)) becomes as shown in FIG. 1. Referring to the figure, numeral 1 designates a laser, and a laser beam 2 emerging therefrom is focused by a lens 3-1 into a point source. The laser beam is focused by an optical system of a lens 3-2, and then thrown on a specimen 4 situated at a focal plane. For the focused laser beam 2, a lens 3-3 and an aperture 5 are arranged in a confocal positional relationship. The laser beam 2 transmitted through the specimen 4 falls on the aperture 5, and the laser beam 2 transmitted through the aperture 5 is detected by an optical detector 6. In order to form a picture, while the specimen 4 is being moved within the focal plane by moving a stage 7, the signals of the optical detector 6 in respective places are stored. The stored data of the picture is displayed on a display device 8.
The function of the aperture 5 in the confocal scanning laser microscope is to raise the resolving power, and an aperture of very small diameter is required. The aperture 5 having heretofore been used is formed in a thin metallic plate by an electric discharge process. In this case, when the diameter of the aperture 5 becomes small, there are such disadvantages:
(i) that the formation of the aperture 5 is difficult,
(ii) that the depth of the aperture 5 (the thickness of the thin plate) becomes greater than the diameter of the aperture 5, so the transmission factor of the laser beam worsens, and
(iii) that in case of use, the positioning of the aperture 5 is difficult.